* NEWS, configure.ac: Version 1.20.91

* NEWS, configure.ac: Version 1.20.91
* doc/tar.texi: Document transformation scope flags.
* src/common.h (transform_symlinks_option): Remove in favor of
transformation scope flags.
(XFORM_REGFILE, XFORM_LINK, XFORM_SYMLINK, XFORM_ALL): New macros.
(transform_name, transform_member_name, transform_name_fp): Take
an additional argument, specifying scope flags.
* src/create.c: Reflect changes to transform_name.
* src/extract.c (extract_link, extract_symlink): Remove calls to
transform_member_name. It is done in read_header.
* src/list.c (decode_xform): Reflect change in data type of 2nd
argument.
(transform_member_name): 2nd arg is int.
(decode_header): Transform file name and link target names.
* src/tar.c: Remove --transform-symlinks.
* src/transform.c (struct transform): New member `flags'.
(transform_flags): New variable.
(parse_transform_expr): Parse transformation scope flags. Allow to
set global flags using `flags=' syntax.
(_transform_name_to_obstack, transform_name_fp)
(transform_name): Take an additional argument, specifying scope
flags.